Aluminum reduction pot



J- A. RAMSEY ALUMINUM REDUCTION POT Filed May 29, 1962 INVENTOR.

ATTORNEY April 20, 1965 JAMES A. RAMSEY United States Patent 3,179,736ALUMINUM REDUCTION POT James A. Ramsey, Portland, Tex., assignor toReynolds Metals Company, Richmond, Va., a corporation of Delaware FiledMay 29, 1962, Ser. No. 198,559 Claims. (CI. 13-25) This inventionrelates to an aluminum reduction pot.

For sixty years following the introduction of the Hall process for theextraction of metallic aluminum, the replacement of the monolithiccarbon linings employed in small reduction cells constituted a major andexpensive maintenance problem. Relatively recently the use of pre-bakedcarbon cathode blocks has been adopted providing to the equipment alonger life and a higher operating strength, the blocks themselves beingcharacterized by a higher density, a low porosity, and a lowerresistance than the materials previously employed. Even more recently,it has been found that the use of graphite rather than carbon for thecathode blocks provides further advantages, but because of the brittlenature of tapered end on each collector bar for reception within acomplementary socket formed in the large graphite block. Inasmuch as thecollector bars which are customarily composed of mild steel, will expandat a far greater rate than the graphite with increases of temperature,the tapered ends of the collector bars are slotted so as to relieveexcessive forces that would otherwise fracture the blocks at theelevated temperatures employed,

ranging up to 900 C. Upon establishing a joint of the type contemplatedby the present invention, adequate pressure and conductivity will bemaintained between the graphite block and the collector bars for thelife of the cathode.

It is among the objects of the present invention to provide an aluminumreduction pot comprising a shell, a graphite cathode block supported inthe shell, and a metal collector bar extendingthrough the shell andelectrically connected with the block, the block containing a socketconverging inwardly from a surface thereof. the collector bar having aconvergent end complementing the socket and received therein, theconvergent end containing a slot extending throughout the lengththereof. The convergent end preferably has a taper of the order of 3 andpreferably contains a plurality of such slots disposed perpendicularly.Such slots preferably exceed the length of the convergent end .of thecollector bar.

The present invention also contemplates the provision of an aluminumreduction pot electrical connection between a graphite block and a steelcollector bar wherein the block contains ,a tapered socket and the barhas a tapered end complementing and received in the socket, the end ofthe bar being symmetrically slotted throughout the length of its taper.

A more complete understanding of the invention will follow from adescription of the accompanying drawings wherein:

I ice FIG. 1 is a sectional elevation of an aluminum reduction potincorporating the present invention;

FIG. 2 is a fragmentary sectional elevation on an enlarged scaledepicting a graphite cathode block receiving a tapered endof a collectorbar;

FIG. 3 is a section taken along line 33 of FIG. 2;

FIG. 4 is an end elevation, on an enlarged scale of a collector bar thetype depicted in FIG. 2; and

FIG. 5 is an elevation of a collector bar of the type depicted in FIG.2.

The aluminum reduction pot depicted in FIG. 1 includes a steel retainedshell 10 whose bottom wall is covered by insulation material 12 such asalumina which in turn supports graphitee cathode blocks 14, the sidewalls 16 of the shell being covered with rammed carbon 18.

Collector bars 20 extend through the side walls 16 of the shell 10, andhave tapered ends 22 received in complementary tapered sockets 24provided in the graphite cathode blocks. The angle of taper 0 depictedin FIG. 5 is preferably of the order of 3. The tapered end of eachcollector bar is slotted throughout the length of the taper andpreferably for a distance exceeding the length of the taper. Theslotting is preferably in the form of solts 26 and 28 disposed at rightangles extending throughout the length of the tapered ends 22 and intothe portions of the collector bars of uniform cross section. After thegraphite cathode blocks have been assembled in the reduction pot, thecollector bars are driven into position so that their tapered ends enterinto a snug fit with the sockets provided in the blocks so as to providethe required conductivity. The collector bars can be anchored in thesepositions in any suitable manner and suitable straps 30 can be weldedthereto for the attachment of suitable electric conductors.

Highly satisfactory results have been achieved in accordance with thepresent invention where the collector bars have tapered ends of theorder of twelve inches in length and where the slots are of the order of0.042 inch wide and extend for a length of approximately fourteeninches. Such bars have a maximum cross sectional dimension of the orderof four and one-half inches from which the taper begins.

Whereas only one form of the invention has been described with referenceto the accompanying drawings, variations will occur to those skilled inthe art which fall within the scope of the appended claims.

I claim:

1. An aluminum reduction pot comprising a shell, a graphite cathodeblock supported in said shell, and a resilient metal collector barextending through said shell and electrically connected with said block,said block containing a socket converging inwardly from a surfacethereof, said collector bar having a convergent end complementing saidsocket and received therein, said convergent end containing a slotextending through the length thereof. I

2. An aluminum reduction pot according to claim 1 wherein saidconvergent end has substantially a 3 taper.

3. An aluminum reduction pot according to claim 1 wherein saidconvergent end contains a plurality of intersecting slots extendingthrough the length thereof.

4. An aluminum reduction pot according to claim 1 wherein saidconvergent end contains perpendicular slots extending throughout thelength thereof.

5. An aluminum reduction pot according to claim 1 wherein said slot hasa length exceeding that of said convergent end.

(References on following page) away/3e;

'3 0 References C1100 by the Examiner 2,603,669

UNITED STATES PATENTS 5/07 Newell 33s 250 5 61 4/17 Sandell 1325 X 5 3059 033 8/ 19 Fitzpatrick et a1 1325 X 5/23 Little 338324 X 4/25 Cohen339-273 8/25 Church 338-324 X 164, 0 7/49 Rose et a1. 1331 10/50 Bailey313-357 X m RICHARD Chappell 313-457 X Marinace et a1. 1325 Dieterich1325 X Alexander et a1. 13-25 X Grunert 13-9 FOREIGN PATENTS Sweden.

1. AN ALUMINUM REDUCTION POT COMPRISING A SHELL, A GRAPHITE CATHODEBLOCK SUPORTED IN SAID SHELL, AND A RESILIENT METAL COLLECTOR BAREXTENDING THROUGH SAID SHELL AND ELECTRICALLY CONNECTED WITH SAID BLOLK,SAID BLOCK CONTAINING A SOCKET CONVERGING INWARDLY FROM A SURFACETHEREOF, SAID COLLECTOR BAR HAVING A A CONVERGENT END COMPLEMENTING SAIDSOCKET AND RECEIVED THEREIN, SAID CONVERGENT END CONTAINING A SLOTEXTENDING THROUGH THE LENGTH THEREOF.